1. Field of the Invention
The present invention generally relates to a remote control system. More specifically, the present invention is directed to a remote control system which uses wireless communications to issue command signals.
2. Background of the Invention
Remote control operations are available for various sorts of electronic appliances such as audio/visual appliances, e.g., VTRS, television receivers, and CD players, and also air conditioners, and illumination devices.
Since it is cumbersome to use a dedicated remote commander for each of these devices, methods of operating a large number of appliances by way of a single remote controller have been proposed. One of these single remote commander controlling methods uses a central controller.
In FIG. 1, there is shown an example of a remote control system which employs a central controller. This example is adapted to an A/V (audio/visual) system. The A/V system is so constructed that a VTR 2, a CD player 3, a TV tuner 4, and an optical video disk player (simply referred to a xe2x80x9cvideo disk playerxe2x80x9d hereinafter) 5 are connected via an A/V selector amplifier 6 to a CRT monitor 7 and a speaker 8.
That is, outputs of picture signals SV from the respective VTR 2, TV tuner 4, and video disk player 5 are supplied to a picture input changing unit 6a of an A/V selector amplifier 6 and are selected by the picture input changing unit 6a. The picture signal SV selected by the picture input changing unit 6a, is then supplied to the CRT monitor 7 to output a picture.
L-channel and R-channel audio signals (SAL, SLR) outputted from the respective appliances of the VTR 2, CD player 3, TV tuner 4, and video disk player 5 are supplied to an audio input by an audio input changing unit 6b. Following this, the picture signal selected by the audio input changing unit 6b is amplified by an amplifier unit 6c, and volume controls are performed in the amplifier unit 6c. The resultant audio signals are supplied to an L-channel speaker 8 and a R-channel speaker 8 for outputting sound.
Here, there are provided: (a) a remote controller xe2x80x9cRxe2x80x9d equipped with operation keys to operate various appliances in such an A/V system; and (b) a central controller 1 capable of receiving a command signal from this remote commander R. The remote commander R transmits an infrared command signal modulated with a predetermined carrier frequency which is read by an internal microcomputer of the central controller. An infrared ray receiving unit la is arranged with this central controller and is capable of receiving the infrared command signal transmitted by the remote command R. central controller 1 is connected via control signal lines xe2x80x9cCxe2x80x9d to the VTR 2, CD player 3, TV tuner 4, video disk player 5, A/V selector amplifier 6, and CRT monitor 7, respectively. The respective appliances such as the VTR 2, CD player 3, TV tuner 4, video disk player 5, A/V selector amplifier 6, and CRT monitor 7, can thus can execute operations in response to such command signals inputted via the control signal lines xe2x80x9cCxe2x80x9d and are fetched by system controllers employed in the respective appliances.
The central controller 1 is arranged as shown in, for instance, FIG. 2. That is, an infrared signal received by the infrared receiving unit la is converted into an electric signal. This electric signal is waveform-shaped and then demodulated to obtain a demodulated signal which is supplied as a command signal to a control unit lb. Reference numeral lb1 denotes a CPU in the control unit lb, reference numeral lb2 indicates a ROM for storing various sorts of command signals and operation programs, while reference numeral lb3 denotes a RAM for storing a command signal and the like, for instance, which is produced by a user. It should be noted that reference numeral lb4 indicates a clock oscillator for producing an operation clock of the control unit lb.
The CPU lb1 of the control unit lb reads out either one, or a plurality of required command signals from a ROM lb2 or a RAM lb3 in accordance with the operation program based upon the command signal supplied from the infrared ray receiving unit la, and also outputs the read command signals from an output unit lc to an appliance responding to the command signal. The command signal, or signals outputted from the output unit lc are supplied via the control signal line C to the respective appliances, so that the respective appliances are operated in accordance with the appropriate command signal.
In the A/V system shown in FIG. 1, for example, when a user manipulates the fast forward key for VTR 2 by way of the remote commander R during the reproducing operation of the VTR 2, the central controller 1 receives this command signal and outputs a command signal calling for the fast forward operation to the VTR 2 in response to the received command signal, so that this fast forward operation is executed in the VTR 2.
Also, the central controller 1 may perform various interlocking operation controls in order to simplify user""s operation. For instance, CD reproducing play may be enjoyed by merely operating such an operation key indicative of xe2x80x9cCDxe2x80x9d by way of the remote commander R. That is, upon receipt of the command signal of xe2x80x9cCDxe2x80x9d transmitted from the remote commander R, the central controller 1 sends a power-ON command to the A/V selector amplifier 6, and further sends such a command signal for changing the audio input changing unit 6b into a CD input terminal. Furthermore, subsequently, the central controller 1 transmits a power-ON command to the CD player 3, and then transmits a CD-reproduction command. Under this control, a CD reproduced sound is generated by the speakers 8.
As previously explained, when the central controller 1 receives one command signal sent from the remote controller R, the central controller 1 executes a series of control operation with respect to the relevant appliance, so that operations executed by the user are greatly simplified.
However, there is a problem that when such a central controller 1 is utilized, the respective appliances must be connected via the control signal lines xe2x80x9cCxe2x80x9d, and thus the system setting is very cumbersome. The connecting operations and modifications in the connecting operations are troublesome because the number of signal wiring lines is increased.
Furthermore, to perform connections hardware/software processing arrangements capable of processing the control input terminals corresponding to the respective appliances and the command signals derived from the control input terminals, are necessary. As a result, there is a limitation to the number of appliances which can be utilized in such an A/V system. Another problem is that A/V appliances which are manufactured by different manufactures cannot be used.
To solve these problems and obviate the wiring work involved with the control signal lines C, it has been proposed to use infrared command signals which are transmitted not only between the remote controller R to the central controller 1, but also between the central controller 1 to the respective appliances.
However, the infrared command signals usually have frequencies on the order of 30 to 60 KHz. As a result, if this transmission method is executed without any modification, then the infrared command signal transmitted from the remote commander R to the central controller 1 would interfere with the infrared command signal outputted from the central controller 1, resulting in signal interference.
As a consequence, it is required to temporally shift the transmission of the infrared command signal from the remote commander R to the central controller 1 with respect to the transmission of the infrared command signal from the central controller 1 to the respective appliances. For instance, the central controller 1 should execute such a process for outputting the command signal to the relevant appliance after confirming that a user releases the operation key of the remote commander R, and no command signal is supplied from the remote commander R.
However, to execute such a process, the processing operations executed by the microcomputer of the central controller 1 are numerous and there is a problem that a heavy software workload is induced resulting in a lengthy time delay between the user manipulating the remote commander R and the relevant appliance actually performing the required operation in response to this key operation.
It is, therefore, an object of the present invention to provide a remote control system which can solve the above-described problems.
According to a first aspect of the present invention, a remote control system includes a remote commander and a control apparatus. The remote commander transmits a command signal via a first radio (wireless) transmission medium. The control includes a receiving unit for receiving a transmission signal transmitted from the remote commander via the first radio transmission medium, and a transmitting unit for transmitting a command signal via a second radio (wireless) transmission medium so as to operate a preselected appliance among a plurality of appliances in response to the output signal derived from the receiving unit. It should be noted that the term xe2x80x9cradioxe2x80x9d is, in this specification, used in its broadest sense and encompasses wireless communications in at least the electromagnetic spectrum including infrared radiation.
According to another aspect of the present invention, a remote control system includes a remote commander and a control apparatus. The remote commander includes a first transmitting unit for transmitting a first command signal modulated using a first carrier frequency and which is transmitted using a first radio transmission medium in response to an input operation. The control apparatus includes a receiving unit for receiving the radio transmission signal transmitted from the remote commander and a second transmitting unit for transmitting a second command signal modulated using a second carrier frequency and which is transmitted using a second different radio transmission medium. This second command signal controls the operation of an electronic appliance designated by the remote commander among a plurality of electronic appliances, based upon an output signal derived from the receiving unit. A plurality of electronic appliances each have such a receiving unit for receiving the second command signal outputted from the second transmitting unit of the control apparatus, and operations of these electronic appliances are controlled in response to the output signal issued from this receiving unit.
In accordance with a third aspect of the present invention, there is provided a remote control system including a remote commander, a control unit, a selecting apparatus, and an output apparatus. The remote commander includes a first transmitting unit for transmitting a first command signal modulated using a first carrier frequency via a first radio transmission medium in response to an input operation. The control apparatus includes a first receiving unit for receiving a radio transmission signal transmitted from the remote commander by the first radio transmission medium, and a second transmitting unit for transmitting a second command signal modulated using a second carrier frequency via a second radio transmission medium in response to the output signal derived from the first receiving unit. The selecting apparatus includes a selecting circuit for selecting output signals derived for the first and second electronic appliances, and a second receiving unit for receiving the radio transmission signal transmitted from the control apparatus by the second radio transmission medium. The first and second electronic appliances each has a receiving unit for receiving the radio transmission signal transmitted from the control apparatus by the second radio transmission medium. The operations of the first and second electronic appliances are controlled based upon the output signal derived from the receiving unit. The selecting apparatus controls the selecting circuit in response to the signal derived from the second receiving unit. The output signal derived via the selecting apparatus from either the first electronic appliance, or the second electronic appliance is supplied to the output apparatus.
A further aspect of the present invention obviates the need to connect the controller with the respective appliances by way of the connection cables. As a result, cumbersome work is no longer required during the system setting operation. Furthermore, in accordance with the remote control system of the present invention, interference between the first command signal and the second command signal can be avoided by either differing the first radio transmission medium from the second radio transmission medium, or by setting the carrier frequencies to frequencies which do not interfere with each other.